You've fallen quite lucky with this chap. He was born in 1832 and died in 1916.
He was a Seed crusher and oil merchant, it seems like a family business, his father William Flintan was a wealthy man...in 1870 Robert inherited his father's shares in The Great Western Railway. By 1891 he is describing himself as retired engineer & machine maker, my guess is the stamp is the company letterhead stamp, pity the bottom part can't be read.
Photo from Ancestry.
Article courtesy of The British Newspaper Archive.
I think a nephew (possibly) William Houghton Flintan drowned in a boating accident at Margate in 1874.